Fix build with latest glibc

Fixes:
 - http://autobuild.buildroot.net/results/c7de1a1d01edced2098a804ad87dcb67b5dc6832

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>

diff -durN duma_2_5_15.orig/print.c duma_2_5_15/print.c
--- duma_2_5_15.orig/print.c	2019-10-28 10:21:14.080149620 +0100
+++ duma_2_5_15/print.c	2019-10-28 10:22:01.256151561 +0100
@@ -326,9 +326,9 @@
   if(DUMA_OUTPUT_FILE != NULL)
   {
 #if defined(WIN32) && !defined(__CYGWIN__)
-    fd = _open(DUMA_OUTPUT_FILE, _O_APPEND|_O_CREAT|_O_WRONLY);
+    fd = _open(DUMA_OUTPUT_FILE, _O_APPEND|_O_CREAT|_O_WRONLY, 0600);
 #else
-    fd = open(DUMA_OUTPUT_FILE, O_APPEND|O_CREAT|O_WRONLY);
+    fd = open(DUMA_OUTPUT_FILE, O_APPEND|O_CREAT|O_WRONLY, 0600);
 #endif
     if ( fd >= 0 )
     {
